A standard interface of a CPRI (Common Public Radio Interface, Common Public Radio Interface) is a standard of an interface between a baseband unit and a radio frequency unit that are inside a radio base station, which is initiated and defined by the Common Public Radio Interface. Currently, the CPRI interface is widely used in a base station device of a third generation mobile communications system. An entity corresponding to an REC (Radio Equipment Controller) inside the radio base station is a baseband unit, and an entity corresponding to an RE (Radio Equipment, radio equipment) inside the radio base station is a radio frequency unit.
In a physical layer defined in the CPRI protocol, a super frame is a most basic processing object, and each super frame includes 256 basic frames. When transmission of CPRI data is performed, a frame forming operation is performed on the CPRI data according to a certain format to form a basic frame and a basic frame is used as a unit and transmitted between an REC and an RE or between two REs.
In a CPRI link, an REC is a chain head of the CPRI link, and multiple REs may be connected in sequence after the REC. After organizing to-be-delivered data as a basic frame, the REC transmits the basic frame downstream over the CPRI link in sequence. When basic frames received by an RE form one super frame, the RE forwards the basic frames included in the super frame.
However, in an existing manner, when forwarding data, the RE can forward the data only according to a same rate at which the data is received, so that the RE cannot forward the data according to a rate different from a rate at which the data is received.